Biological basis for politics debated

By AMY CHANG | March 14, 2013

Ever talked to someone from a different political party and wondered what on earth they were thinking? A recent study shows that the difference between how liberals and conservatives make decisions may be more fundamental than you think.  Recent research has found that parts of the brain involved with risky decision-making falls along party lines.

Two years ago political scientists felt the individuality of their ideas threatened when a group of neuroscientists, led by Ryota Kanai of University College London, showed they could predict political affiliation by looking at brain morphology, specifically the region that is responsible for risk-taking. The four key regions of the brain involved in thinking about risk and uncertainty are the right amygdala, left insula, right entrohinal cortex and anterior cingulated cortex (ACC).

They found that the ACC, which deals with conflict, error, reward anticipation and decision-making, tended to be larger in liberals, while conservatives typically had bulkier amygdala, the region that handles memory encoding, making social judgments and fear conditioning.

These differences in brain morphology were able to predict political affiliation with 71.6 percent accuracy, indicating that the effectiveness of simple brain scan trumps the current prediction model, which identified with 69.5 percent accuracy by looking at the political affiliations of a subject’s parents. A team of neuroscientists, led by Darren Schreiber of the University of Exeter and Central European University, decided to see if there was a functional disparity that explained this differentiation between parties.

Schreiber’s team looked at brain imaging data from a previous study in which the subjects had been asked to been asked to do a completely non-political task: gambling. The study had participants play a game where they could either win or lose money by pushing a button in response to seeing a number on screen while their brain activity was measured through a process called functional magnetic resonance imaging (fMRI). Schreiber’s team reused this data by looking up the subjects’ political affiliations. They then split the images into liberal and conservative groups to see if there was any connection between how different parties thought about risk.

The researchers found that both parties took the same amount of risk overall, but that different parts of the brain activated when they made risky-decisions. Republicans showed more activity in the right amygdala which focuses attention on external cues, while the Democrats’ brains were more active in the left posterior insula, a part of the brain crucial for subjective feeling and awareness of internal physiological cues.

They concluded that the underlying neural processes of evaluating decisions were different between liberals and conservatives. Furthermore, Schreiber and his team found that when they looked at areas of brain activity to predict a subject’s political affiliation, the scientists were correct 82.9 percent of the time, suggesting this method to be far superior than looking at brain morphology.

“Parental socialization is really powerful until you leave home,” Schreiber said. He explained that once you depart from your parents and develop your own ideologies, the heritability of political ideology can drop close to 40 percent. His research, published in PlosOne, cautioned that while the study does show that biological factors correlate with different sets of political values, the study does not suggest that political inclinations are genetically predetermined. Schreiber sees his study as adding to the understanding of human nature.

“Locke was wrong and B.F. Skinner was wrong,” Schreiber said. “What this says is [that] we are a product of genes, environment and to some extent our own choices … this is a better model of human behavior that also fits better with average intuition.”

“I see this study as a really important part of the larger picture,” John Hibbing, professor from the University of Nebraska-Lincoln, said. “...this is one of the few that looks at the brain when it’s responding … There haven’t been that many studies to look at this.”

Hibbing believes the reuse of the previous data set was creative but that he’d also like to see some other tasks than risk-tasks in future research. “But presumably, that will come,” he said.

”This could be really important for changing the way we understand how ideology and partisanship can be formed in time,” Douglas R. Oxley of Texas A&M University said. “Many social scientists are still in the mode of thought of ‘socialization is the primary factor in party ID.’” However, with the number of studies on the connection between biology and ideology growing, they may have to rethink this notion.

 

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